List email addresses for notifications explicitly in JPA Jenkinsfile

Because this step now runs outside of a node, so it cannot load a
configuration file.

Author: yrodiere

ci/jpa-3.2-tck.Jenkinsfile

@@ -191,7 +191,7 @@ pipeline {
 				sh "docker rm -f ${containerName}"
         	}
     		configFileProvider([configFile(fileId: 'job-configuration.yaml', variable: 'JOB_CONFIGURATION_FILE')]) {
-            	notifyBuildResult maintainers: (String) readYaml(file: env.JOB_CONFIGURATION_FILE).notification?.email?.recipients
+                notifyBuildResult maintainers: "[email protected] [email protected] [email protected] [email protected]"
             }
         }
     }